[xaief] Download RMU Luchs fonts from RMU

Jakob Erbar’s Art Deco font ‚Lux‘, released by Ludwig & Mayer in 1929, completely redrawn and redesign. The German umlaut glyphs Ä, Ö, and Ü come in their original form in the uppercases; in the lowercases the dieresis was placed above the letters.